EPE Association: EPE 2015 - LS6a: Advanced Power Converter Topologies

EPE 2015 - LS6a: Advanced Power Converter Topologies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2015 ECCE Europe - Conference > EPE 2015 - Topic 02: Power Converter Topologies and Design > EPE 2015 - LS6a: Advanced Power Converter Topologies

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   A Smart Current Modulation Scheme for Harmonic Reduction in Three-Phase Motor Drive Applications
By Pooya DAVARI [View]
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Abstract: Electric motor-driven systems consume considerable amount of the global electricity. Majority ofthree-phase motor drives are equipped with conventional diode rectifier and passive harmonicmitigation, being witnessed as the main source in generating input current harmonics. While manyactive harmonic mitigation methods have been developed over the years, the total cost and complexityhas become the main obstacle in employing prior-art methods for motor drive systems. This paperpresents a novel current modulation method based on the electronic inductor concept for three-phaseac-dc systems to reduce input current harmonics. The obtained results at simulation and experimentallevels confirm the effectiveness of the proposed approach.

   An Improved Space Vector Modulation Strategy for Three-Level Five-Phase Neutral-Point-Clamped Inverters
By Cheng TAN [View]
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Abstract: Switched inverters generate fast rates of change of common-mode voltage and are an unwanted sideeffectin variable speed drive systems operated with PWM inverters. Whilst techniques have beenreported that theoretically eliminate the common-more voltage, when the dead-time effects and thepractical transient performance of semiconductors are considered, a common-mode voltage is stillgenerated, even though these proposed techniques sacrifice dc-link utilization and switching loss. Inthis paper, a switching strategy is proposed for the three-level five-phase neutral-point-clampedinverter, which reduces the common-mode voltage as far practically possible and eliminates vectors inthe d2q2 plane. The proposed method maintains the same linear modulation range as the conventionalspace vector modulation technique but utilises fewer switching actions in one carrier period. Moreover,its complexity is reduced lowering the computational overhead. The proposed method is verified inboth simulation and experiments on a prototype of five-phase neutral-point-clamped inverter.

   Evaluation for Overall Volume of Capacitor and Heat-sink in Step-down Rectifier using Modular Multilevel Converter
By Toshiki NAKANISHI [View]
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Abstract: This paper discusses a volume evaluation of a step-down rectifier using a Modular Multilevel Converter (MMC) for a power system connected to a utility gird of 6.6 kV. in order to obtain the high power density. Specifically, this paper evaluates a relationship among an output voltage of the MMC, a volume of capacitors and a volume of a heat-sink. At first, formulas of semiconductor losses are clarified. Second, the relationship among the ripple current and the volume of electrolytic capacitors is considered. In addition, the relationship between the number of cells per leg and an overall volume is also shown. According to these considerations, the evaluation result of the overall volume shows that it is necessary to reduce a step-down ratio of the MMC in order to obtain the high power density. Moreover, it is also necessary to approach a withstand voltage ratio to 1.0 when the withstand voltage ratio is defined as the ratio of the required withstand voltage to an actual withstand voltage with series connection capacitors. In conclusion, the volume of the proposed system becomes approximately 20\% of the volume of a conventional power system of 200 kVA connected to a utility gird of 6.6 kV.

   Voltage Stress on Power Switches in Active NPC Topologies
By Lorenzo GIUNTINI [View]
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Abstract: Neutral-Point-Clamped topologies have been widely applied to improve power conversion efficiency. Active NPC variants may offer an advantage in terms of efficiency and losses distribution. Remarkably, Active NPC topologies differ from traditional NPC in terms of power semiconductors characteristics and commutation paths. This paper investigates Active 3L NPC converters in double-conversion UPS applications. Particularly, it discusses voltage stress on power switches in Active NPC converters, presenting experimental results from high-power 3ph UPS implementation.

EPE 2015 - LS6a: Advanced Power Converter Topologies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2015 ECCE Europe - Conference > EPE 2015 - Topic 02: Power Converter Topologies and Design > EPE 2015 - LS6a: Advanced Power Converter Topologies
	[return to parent folder]

	A Smart Current Modulation Scheme for Harmonic Reduction in Three-Phase Motor Drive Applications By Pooya DAVARI	[View] [Download]
Abstract: Electric motor-driven systems consume considerable amount of the global electricity. Majority ofthree-phase motor drives are equipped with conventional diode rectifier and passive harmonicmitigation, being witnessed as the main source in generating input current harmonics. While manyactive harmonic mitigation methods have been developed over the years, the total cost and complexityhas become the main obstacle in employing prior-art methods for motor drive systems. This paperpresents a novel current modulation method based on the electronic inductor concept for three-phaseac-dc systems to reduce input current harmonics. The obtained results at simulation and experimentallevels confirm the effectiveness of the proposed approach.

	An Improved Space Vector Modulation Strategy for Three-Level Five-Phase Neutral-Point-Clamped Inverters By Cheng TAN	[View] [Download]
Abstract: Switched inverters generate fast rates of change of common-mode voltage and are an unwanted sideeffectin variable speed drive systems operated with PWM inverters. Whilst techniques have beenreported that theoretically eliminate the common-more voltage, when the dead-time effects and thepractical transient performance of semiconductors are considered, a common-mode voltage is stillgenerated, even though these proposed techniques sacrifice dc-link utilization and switching loss. Inthis paper, a switching strategy is proposed for the three-level five-phase neutral-point-clampedinverter, which reduces the common-mode voltage as far practically possible and eliminates vectors inthe d2q2 plane. The proposed method maintains the same linear modulation range as the conventionalspace vector modulation technique but utilises fewer switching actions in one carrier period. Moreover,its complexity is reduced lowering the computational overhead. The proposed method is verified inboth simulation and experiments on a prototype of five-phase neutral-point-clamped inverter.

	Evaluation for Overall Volume of Capacitor and Heat-sink in Step-down Rectifier using Modular Multilevel Converter By Toshiki NAKANISHI	[View] [Download]
Abstract: This paper discusses a volume evaluation of a step-down rectifier using a Modular Multilevel Converter (MMC) for a power system connected to a utility gird of 6.6 kV. in order to obtain the high power density. Specifically, this paper evaluates a relationship among an output voltage of the MMC, a volume of capacitors and a volume of a heat-sink. At first, formulas of semiconductor losses are clarified. Second, the relationship among the ripple current and the volume of electrolytic capacitors is considered. In addition, the relationship between the number of cells per leg and an overall volume is also shown. According to these considerations, the evaluation result of the overall volume shows that it is necessary to reduce a step-down ratio of the MMC in order to obtain the high power density. Moreover, it is also necessary to approach a withstand voltage ratio to 1.0 when the withstand voltage ratio is defined as the ratio of the required withstand voltage to an actual withstand voltage with series connection capacitors. In conclusion, the volume of the proposed system becomes approximately 20\% of the volume of a conventional power system of 200 kVA connected to a utility gird of 6.6 kV.

	Voltage Stress on Power Switches in Active NPC Topologies By Lorenzo GIUNTINI	[View] [Download]
Abstract: Neutral-Point-Clamped topologies have been widely applied to improve power conversion efficiency. Active NPC variants may offer an advantage in terms of efficiency and losses distribution. Remarkably, Active NPC topologies differ from traditional NPC in terms of power semiconductors characteristics and commutation paths. This paper investigates Active 3L NPC converters in double-conversion UPS applications. Particularly, it discusses voltage stress on power switches in Active NPC converters, presenting experimental results from high-power 3ph UPS implementation.